More and more dynamic positioning ships choose to use closed-loop power grid systems in the design of the power distribution networks in order to save energy and reduce emissions, operate economically, and improve the reliability and flexibility of power distribution networks. DNV, ABS, CCS and other classification societies have also put forward corresponding inspection requirements for the design of closed-loop power grids in specifications and guidelines, among which advanced generator protection is one of the key points of the reliability assessment of the closed-loop power grids by these classification societies. Based on the specification requirements for the advanced generator protection, the design points of the advanced generator protection are analyzed from typical power grid faults combined with the current practical applications. It is hoped to provide references for the subsequent design of the closed-loop power grid.

For crane ships, the DP-2 lifting operation mode is the most critical operation mode for crane ships. Especially the this article introduces and analyzes the electrical design of the 3 000 t full revolving floating crane vessel. It firstly analyzes the characteristics of its electrical system design, mainly including the application of the power distribution system architecture, the dynamic positioning (DP-2) system and the anchor mooring positioning system on the crane vessel. The electrical design of the full revolving floating crane vessel is deduced based on the FMEA report. A design scheme that meets the requirements of navigation and operation, and the solutions for some important problems have been proposed according to the particularity of this crane ship. The similarities and differences between this crane ship and the previous crane ships are analyzed to provide reference for the electrical system design of this type of subsequent ships. It is also hoped to provide the more in-depth discussions and the better optimization schemes for the electrical design of the offshore engineering crane ships.